Leafy Vegetables and Agrivoltaics

One of the characteristic agricultural products grown under agrivoltaics is leafy vegetables such as cabbage and lettuce. 

Since they are easily affected by strong sunlight, shading with solar panels will help the growth of leafy vegetables.

Growing Cabbage and Lettuce

In the lowlands of Japan, summers are too hot for growing leafy vegetables. However, solar sharing makes it possible to grow leafy vegetables by blocking the strong summer sunlight.

Another known benefit of the presence of solar panels is that they help to control frost in winter. Therefore, in areas where leafy vegetables could not be grown in the winter, it has become possible to grow cabbage and other crops through solar sharing.

Of course, it's not just good for leafy greens. Shading by solar panels delays the drying of the ground after rain. This can lead to disease outbreaks due to moisture damage.

Nevertheless, the advantage of being able to grow vegetables that could not be grown within the region before will bring about a very significant change.

The Japanese Government's New Basic Energy Plan and Agrivoltaics

Currently, the Japanese government is formulating a new mid-term plan for energy policy. This plan includes a target for the introduction of renewable energy in 2030, and the figures are attracting attention.

The draft of the plan was released on July 21, and in it, the target for Japan's introduction of renewable energy in 2030 was presented as 36% to 38%. Other than renewable energy, nuclear power accounts for 20% to 22%, and thermal power accounts for about 41%.

Unfortunately, this is not an ambitious goal at all, but given Japan's lagging status in the international community, it is a figure that will require a great deal of effort to achieve.

Among renewable energies, there is no other option but to greatly increase solar power, but here again, unfortunately, the target was not ambitious enough to introduce it. The figures remain very ambiguous.

The Japanese government did not adopt the private sector's proposal that two to three times the amount of solar power generation equipment will be needed compared to 2020. In this draft, the introduction target is stuck at 100 GW.

The reason for this was the reluctance to include farmland in the piling up of numbers on where to build more solar power plants.

However, additional 50 GW to 100 GW can easily be introduced by using agrivoltaics, and more steps should be taken to promote renewable energy that coexists with agriculture.

How to Choose PV modules for Agrivoltaics in Japan

Agrivoltaics in Japan has involved a unique selection process for PV modules. Slim PV modules were favored when they were first popularized in 2013. The purpose of this was to ensure that solar radiation would hit crops as evenly as possible and to prevent damage to equipment from strong winds.

Fujidana style solar sharing with slim PV modules

At the time, Japan's high cost of FIT made it possible to use these specially designed solar panels. By adopting the slim type, the project cost will be 30% to 50% higher than that of ordinary industrial solar panels.

This is limited to the Fujidana style solar sharing design, while the array type design uses larger products from the beginning.

Since around 2017, normal, larger products have gradually come into use, partly due to changes in the market, such as the need to improve business viability as a result of lowered FITs and the withdrawal of manufacturers producing slim types.

Fujidana style solar sharing with large modules

The latest design of the Fujidana style solar sharing minimizes the impact on growth through precise simulation of solar radiation on crops. Improvements in design have also made it possible to withstand large typhoons. As a result, the need to adopt slim-type products is now decreasing.

In the future, research is being conducted on the use of double-sided glass solar panels to improve durability and increase solar radiation while also ensuring economic efficiency.

Increase in agricultural participation triggered by Agrivoltaics

The spread of agrivoltaics has encouraged new entrants to agriculture in Japan.

As of 2020, the agricultural population in Japan has declined to one-tenth of what it was 60 years ago. The average age of farmers has reached 67, so we need to increase the number of young people entering the industry.

Strangely enough, more and more young people and businesses in Japan are taking advantage of agrivoltaics to enter the agricultural industry.

Young people in their twenties are moving toward agriculture

Currently, solar power companies in Japan are actively engaged in agrivoltaics. It is not uncommon for businesses that have been involved in the solar power business to enter the agriculture industry by getting involved in agrivoltaics.

It seems that this experience with renewable energy has sparked an interest in agriculture.

So why is the younger generation interested in this? It is probably because they have a stronger interest in energy and agricultural sustainability.

The income from energy makes it easier to engage in agriculture. And there is a growing trend to use renewable energy in agriculture, rather than simply selling electricity.

The time will soon come when solar sharing will be the common choice for newcomers to agriculture.

Design Patterns for Agrivoltaics in Japan

The design of Agrivoltaics or solar-sharing systems in Japan has changed significantly since the start of their widespread use in 2013.

The concept of the project was divided into two main categories: prioritizing agriculture and prioritizing the power generation business. The decision has been made to prioritize reasonable profits from power generation projects in the face of severe cost tightening by Japan's FIT, or to pursue designs that are more suitable for farming and crops.

The one that has been prioritizing the profitability of the power generation business is a design known as the Array type. This is simply a taller pillar of the racks used in ordinary ground-mounted solar power plants.

Array type solar-sharing

In the case of the array system, it can be installed at a cost not much different from that of a ground-mounted solar power plant, but the shading rate may be uneven and agricultural machinery may be difficult to use.

In contrast, the Fujidana style design, in which solar panels are installed evenly, has been actively adopted. This design has been adopted with the idea of prioritizing farm work and agricultural production.

Early Fujidana style solar-sharing

In the early stages of the widespread use of solar sharing, the use of slim solar panels was favored in addition to this uniform solar panel design. However, this custom-made solar panel has become less common in recent years due to the increasing difficulty in obtaining them.

For the past three years or so, there has been an increase in the use of Fujidana style mounts with large solar panels as a design that allows for both farming and power generation projects.

The latest model of Fujidana style solar-sharing

Utilization of Renewable Energy in Agriculture

Agrivoltaics allows us to secure large amounts of electricity on farmland, and we are working on ways to use it for agriculture.

Although large agricultural machinery such as tractors have not yet been electrified in Japan, demonstration experiments are underway with small agricultural machinery and electric vehicles.

The installation of these machines that utilize the electricity from agrivoltaics will help decarbonize agriculture and rural communities.

Toyota Auto Body's ultra-compact electric vehicle

Radio-controlled electric agricultural machinery

In rural areas, life would not be possible without automobiles. In the past three years, Japan has experienced multiple large-scale power outages, which has drawn attention to the introduction of electric vehicles powered by local renewable energy.

The rural village where we are doing agrivoltaics also experienced 8 days of power outage in 2019 due to typhoon. At that time, we could no longer get enough gasoline for our cars.

Based on this experience, the use of electricity from agrivoltaics for mobility has made it possible to secure a means of transportation and power source in times of disaster.

In the future, we will introduce more electric agricultural machinery to improve agricultural productivity and decarbonization.

Rice Farming and Agrivoltaics

Rice is the staple food of the Japanese people, and rice farming is also being used in agrivoltaics.

A shading ratio of around 35% is suitable for growing rice, and famous varieties such as Koshihikari and Akitakomachi are grown here.

Planting of Akitakomachi rice

Impacts on the growing environment include slightly cooler water temperatures and delayed ripening, which generally delays the harvest time by about one week.

However, a slight delay in growth is not a problem for farmers, as the income from the sale of electricity from solar power generation is about 10 times higher than the production value of rice.

Since it is not practical to install agrivoltaic systems in all the paddy fields without any gaps, only some of them are installed to support the farmers' income.

With the increasing automation of agricultural machinery used in paddy fields, the decline in workability and other problems are expected to eventually improve.

About crops grown under agrivoltaics in Japan.

A wide variety of crops, including grains and vegetables, are grown in agrivoltaics in Japan. It can be installed on a variety of farmland, but there is a regulation that the yield must not be reduced by more than 20% from the regional average.

Soybean

Eggplant

Taro

In Japan, half of the country's agricultural land is paddy fields, which produce rice, the country's staple food. Rice can be grown without any problem if the shading ratio of agrivoltaics is about 35%.

Paddy field

Data on the shading rate of agrivoltaics and crop growth has been accumulated, and the future challenge is to improve productivity by taking advantage of the shading environment.

Agrivoltaics system in Japan

Agrivoltaic is called "solar sharing" in Japan. In 2013, the Ministry of Agriculture, Forestry and Fisheries (MAFF) set up a system that began to spread, but a small number of power plants had been installed before then.

Power plants installed in the early years

The term "solar sharing" is used by the private sector, while the Ministry of Agriculture, Forestry and Fisheries uses the term "farm-based solar power generation". In English, the official term is "Farming Photovoltaics".

Reference: MAFF special website on Farming Photovoltaics.

https://www.maff.go.jp/j/shokusan/renewable/energy/einou.html#guidebook

96 power plants were installed in 2013, and the number has been hovering around 300 to 400 annually since then. Most of them are using the Feed-in Tariff.

In Japan, solar sharing is given special treatment under the Agricultural Land Law, and can be installed even on agricultural land, where use for anything other than agriculture is strictly restricted.

Since the system was launched with the aim of improving the income of farmers, it is characterized by a high degree of flexibility in terms of installation locations.

About Agrivoltaics Japan

This blog will provide information on Agrivoltaics in Japan, which is not very well known.

In Japan, an initiative called solar sharing or Farming PV is spreading.

Let's take a look together at the new future painted by the collaboration between renewable energy and agriculture.